1. Field of the Invention
The field of the invention is removable inserts for construction work and especially inserts for forming holes in concrete and the like particularly in the construction of manholes.
2. Description of the Prior Art
In the construction of manholes it is necessary to provide steps which is sometimes done by creating holes in the manhole wall during the construction thereof and thereafter using a prefabricated plastic step, such as the step disclosed in U.S. Pat. No. 4,100,997, to be driven into the holes in the manhole. If the manhole is constructed from poured concrete it has been the practice in the past to provide inserts in the concrete which are removed after the concrete has cured to leave the holes. This has involved the use of pins and inserts and angle iron supports to place the inserts in the proper position and to make it possible to remove the inserts with a minimum of difficulty. Still there has been a problem in connection with the proper positioning of the inserts and particularly with respect to the removal of the inserts after the concrete has cured (sometimes called stripout). A lever bar is used to move two pins connected by steel plate or angle iron. During removal the pin-plate assembly will cock and jam making removal time consuming and difficult.